However, the domestication history of zebrafish laboratory strains is longer (c. 30 generations) than in S. salar and may involve bottlenecks, which might lead to false-positive signals of selection (Whiteley et al. 2011).
That year, the problem involved railroad bottlenecks in getting coal to power plants — an issue largely resolved with the subsequent investments in more rail lines.
First, continued evolution of R5 viruses in PBMCs, spleen and lymph nodes involved multiple bottlenecks, independent of coreceptor switch, resulting in fitter quasispecies driven by positive selection.
However, this was likely to be rare since phage densities only approached those of hosts late during flask growth, and each transfer involved a bottleneck to a smaller population size such that co-infected hosts would be subject to strong sampling effects.
We postulate that the factors involve possible bottlenecks in service provision over weekends and after office hours.
This assumed demography, involving periodic bottlenecks where the number of individuals is fixed, is typical of most experimental setups, where daily passages of a sample of the population are performed, and population numbers are experimentally controlled.
However in spite of recent successes, the path to a high-resolution structure of a membrane protein still involves several bottlenecks including poor expression, limited extraction success, low purification yields and paucity of well-ordered 3D crystals (Fig. 1).
This probably implies a genetic bottleneck in rice, secondary to a bottleneck of initial cultivation and any bottlenecks involved with post-Pleistocene expansion.
The ones I've been to have been well run, despite the inevitable bottlenecks involved in loading ferries.
These efforts are usually focused in redirecting precursor metabolic fluxes, deregulation of biosynthetic pathways and overexpression of specific enzymes involved in metabolic bottlenecks.
